Diesel multiple unit trains wheel set maintenance modelling, simulation and optimisation

This paper presents the modelling and simulation of Class 170 wheel sets for a fleet of trains in Scotland. A description of the wheel set defect challenges and the evaluation of the maintenance practices of the wheel sets are presented in this paper. An alternative non destructive testing (NDT), remote condition monitoring and maintenance optimisation of the Class 170 wheel sets of the trains is discussed. All Class 170 wheel set associated failure modes and maintenance requirements are analysed using the reliability centred maintenance (RCM) approach. The failure modes identified maintenance optimisation simulations are conducted using the specialist RCMCost Availability Workbench (ISOGPRAPH) simulation software by fitting a Weibull model to the data. An optimum cost effective preventive maintenance schedule and periodicity is achieved and as a result contributes 21% to 50% labour cost savings over a period of three years. The proposed evaluation technique to eliminate intrusive ultrasonic axle testing through the alternative NDT technology to detect sub surface cracks or flaws does not identify any ideal solution for a high maintenance turnaround environment. However, remote wheel slip protection condition monitoring solutions present the opportunity to proactively identify wheel slip events in-service that contribute to the early manifestation of wheel tread defects. This identification system enables the maintenance manager to optimise maintenance planning, improve fleet availability, maintenance efficiency, and operational safety, maintain quality and increase the wheel set functional life.